A greenhouse temperature control device comprises a power module, a control module, a heating module and a cooling module, wherein the control module comprises a control processor and a temperature sensor, the temperature sensor, the heating module and the cooling module are all located on the inner side of a greenhouse, the heating module comprises an electric heating net, a fan and a hot air pipeline, the electric heating net and the fan are both located on the side, provided with an air inlet, of the hot air pipeline, the fan supplies air into the hot air pipeline through the air inlet, the hot air pipeline is horizontally located on the top of a greenhouse, a plurality of air outlets are formed in the side face of the hot air pipeline, the cooling module comprises a first exhaust fan and a second exhaust fan, the first exhaust fan supplies air to the inner side of the greenhouse, the second exhaust fan supplies air to the outer side of the greenhouse, and the electric heating net, the fan, the first exhaust fan and the second exhaust fan are all controlled by the control processor to operate.